As known, a packaging line of the above type comprises, in general, a packaging machine which is adapted to form the packages with the product already inside. In particular, the packages are generally produced from a sheet packaging material, which is normally in the form of pre-cut blanks or a continuous strip, and which is subjected to a series of folding and longitudinal sealing operations to form a continuous tube of packaging material, which, after being filled, is welded, transversely divided and formed to take the form of individual packages.
The packages are then supplied to a grouping unit to be arranged in groups of a given number of packages and advanced, finally, to a wrapping machine to be wrapped by a wrapping material, normally cardboard or plastic film, and to form multipacks.
Depending on the size of the multipack, the packaging line may have a single-line or a multi-line configuration. In the latter case, immediately upstream from the grouping unit there is normally arranged a divider, which is adapted to remove the packages from an output of the packaging machine and to distribute the packages, aligned with one another, in a determined number of parallel lines. The grouping unit is configured to group the packages in each line and order the groups along the respective lines to allow a transfer device to withdraw a group from each line, simultaneously, and feed the groups to the wrapping machine to be arranged in a compact configuration and wrapped to form a multipack.
Regardless of the multipack format and, therefore, of the number of lines of the grouping unit, it is known that the transfer of the packages from the packaging machine to the wrapping machine is a very critical stage for the stability and integrity of the packages. This stems from the fact that the package output linear speed from the packaging machine is normally considerably higher than the speed with which the groups are fed to the wrapping machine and it is essential to slow down the packages which are fed with high speed to the grouping unit in order to ensure that the linear speed of the groups fed to the wrapping machine and the wrapping machine input speed are equal.
Since at this stage the packages are subjected to a relatively high reduction of the advancing speed, especially in view of the high production speed of the new generation packaging machines, it is very important to reduce the linear speed of the packages in a manner as controlled and gentle as possible to avoid dropping of packages or damage thereof.